The present invention relates to a floor tile, and more particularly to a floor tile adapted to interengage with a corresponding floor tile with a fit of the tongue and groove type. In this specification the words "tongue and groove type" are used in a broad sense and merely indicate that the tiles are provided with interengaging profiles at their side edges.
Many different types of floor tile have been proposed before, and in particular floor tiles comprising laminates of different layers have been proposed. One proposed floor tile comprises a supporting base plate or carrier layer which carries a floor surface forming layer. The carrier layer comprises, for example, a rectangular plate formed of laminated wood or plywood, and the floor surface forming layer comprises a decorative layer such as varnished parquet blocks.
To facilitate the laying of such prior proposed floor tiles various types of tongue and groove arrangements have been utilised. Tiles with such tongue and groove arrangements are becoming increasingly popular since they have the advantage that they are easy to lay, and thus it is not necessary to utilise trained personnel to lay such floor tiles.
However, prior proposed floor tiles have suffered from disadvantages. If the floor surface forming layer of the floor tile is to be both decorative and, at the same time, resistant to wear, the decorative layer must be of considerable thickness. From the economic point of view this limits the choice of materials available. Furthermore, only hard materials, such as hard woods, may be used if permanent marking is to be avoided at points where the floor is subjected to a high load, for example if the floors are walked on by persons wearing pointed high heels.
A further disadvantage experienced with prior proposed floor tiles is that it is not easy to lay such tiles with only very narrow joints between the adjacent tiles. It is to be appreciated that it is desirable to be able to lay tiles with only narrow joints between adjacent tiles both for the sake of the appearance of the tiled floor, and with regard to hygienic considerations. Of course, it must be borne in mind that the joint itself must be relatively strong so that the joint is not damaged if the joint itself is subjected to point loading.
Where a tiled floor is to be laid on a concrete foundation it has been proposed that the tiles should be laid on a waterproof diffusion barrier. Such a barrier may comprise overlapping layers of asphaltic felt which has cork fragments baked into the asphalt layer so that the tiled floor exhibits a certain resilience. However, even with this expedient, the moisture content of the tiles varies at different times of the year causing the tiles to expand and shrink. Consequently the tiles are therefore normally glued together in the region of the tongue and groove joint to prevent the joints between adjacent tiles expanding and contracting. However, with prior proposed tongue and groove joints it has been found difficult to perform such a glueing step in a satisfactory manner. It has been found that glue often exudes up between the floor tiles and collects on the upper surface of the floor tiles. This is quite unacceptable if the floor tiles are surface treated during manufacture so that, when laid, the surface tiles have a perfect finish, or when the decorative layer is too thin to permit grinding of the floor after the glueing process.